Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
J F~Eh~IEF IEl_ TEL h~lo . X13-64~~-~53U Jarr .2~1 , 91 .l ~ :Oh F' . u::l
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METHOD AND APPARATUS FOR FORhIING AN
AZR BAG DEPLC7YMENT OP~NIfG
Background of the Inventi_pn
7.. Field of the lnvent~.on
This invention concerns air bag safety devices :for auto
vehicles which have been devised to be deployed during a severe
collision to cushion the driver andjor passengers to prevent or
reduce the severity of ln~uries.
2, Description of 'the Prior Arty
In air bag installations, an air bag "oannister"", caiapr icaed
c;~ a rouoptacle holding rx t'olded fir bag ant <w :w,n:~.'L~:~~hian
a~tpar atus, is sl.ored h~thi.nct tt s~aat;.:lor1 0~' art auto i.ot"~zr-~.or
v,rim
parle7,, .suoh as the instrument pano7. (passenger side bag) or
steering wheel cover (driver side bag) . The air bag :is ~.nvlated
to be deployed within the passenger compartment as the collision
occurs, and thus must enter the passenger compartment through an
opena.ng ~.n the trim panel. Typical~.y, a pair of doors. are
installed in a vert~.c~nl rear facing surface of the instrument
panel, (m~.d mount) or steering wheel cover, or a single Boar, is
pxovided in an upper surface o#' the instrument penal (top mount).
xhe dears are designed to be apenad by the air bag as ~.t ~.nf:lates
during deployment.
A drawback to the prior designs is that the doors are
exteriorly visible, i.e., are apparent to the driver or passenger
seated in the passenger compartment, which visibility creates a
mild state of apprehension in some persons.
CA 02008728 1998-11-20
Also, the separate door construction adds to the cost of
the interior trim, and may adversely affect the aesthetics of the
interior finishing.
Examples of such deployment door designs are described
in commonly assigned Canadian patent applications nos. 610,624 of
September 7, 1989 and 2,000,642 of October 13, 1989.
It is an object of the present invention to provide an
apparatus for forming an air bag deployment opening in an interior
trim panel in which there is no visible delineation of the opening
prior to activation of the air bag.
It is a further object of the present invention to
provide such apparatus which does not require a separate door
closure assembly to be installed in the interior trim piece
defining the opening, and which is simple and failsafe in
operation.
Summary of the Invention
These and other objects of the present invention which
will become apparent upon a reading of the following specification
and claims are achieved by a method and apparatus involving the
application.of a pattern of concentrated energy to the inside of
a trim panel, just prior to inflation of the air bag device, the
pattern delineated in the shape of a required deployment opening.
Such energy may be generated and applied by the ignition of a
segment of low power detonating cord, and almost instantaneously
forms a door in the trim panel behind which the air bag is stored
which may be pushed open a split second later by the inflating air
bag which is thereby able to be deployed through the resulting
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J HEhIEFIEL TEL I~~1o.31~~-G!l~l-E>~3U Jan.?~1.~1 13:U~ P.OE=
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opening.
~fhe dear and trim piece may traus be of integral.
construction, without any exterior markings suggest~.ng the
presence of the air bag device, and affer.i_ng superior aesthetics
end lower costs over designs having separately assembled doer
panels.
preferably, the reverse ar inside face of the trim panel is
formed with a groove delineating the dear shape and which
receives the energy applying element, ~..e., the detonator cord
segment.
Pr~~ferabl.y a rigid br.tctging pieces reinfax~c:e~i the ac~a~~ac~nt
r-~eat:.~.crns cat' tr, im panE~l. an ~a~,thar faiGla of t:lxe c,~xacove,
at~cl ~,:a
formed w.i.th a fo:~c:1 clo4~a.nc~ off ~hr~ ctrauve s~~~acc-a t:c~ cl.~rcu:~t:
l:Itre
energy outward towards the joining segment of panel material, to
more efficiently produce fracturing of the segment and formation
of the door shape in the trim panel.
Description of the Drawings
~ FIGtIttE 1 is a fx~agmenfiary perspective ~riew of the interior
of an automotive passenger compartment having both a driver and
passr~ng~r. side air ba.g insta~.latian, with the location and shape
of an air bag deployment doer indicated therein.
FIGURE 2 is g fragmentary enlarged perspective view of the
passenger side air bag installat~.c~n Shawn in ~'rGURE 1 shbwing
additional details o.f the apparatus far farming a deployment
c~pen.ing .
FIGURE 3 is a perspective view of a portion of the passenger
compartment chown in FIGURE 1, depictinr~ an alternate passenger
3
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aide air bag installation.
FIGURE 4 is a fragmentary sectional view taken through the
instrument panel structure in the embodiment of FIGURE 2.
FIGURE 5 is a fragmentary enlarged perspective view of the
passenger side air bag installation shown tn FIGURE 3 showing
additional details of the apparatus for forming a deployment
opening.
FIGURE 6 is an enlarged fragmentary sectional view taken
through the instrument panel of the embodiment of FIGURE 3 in the
region whereat the deployment opening is to be formed.
p~st~ile_:d pescri flan
'fin the follawin<.l detailed d~x~sarlptlov, cu3rt;~zi.n rtspoa;L~i.~;
tarm:lnalogy w17.1 be on~p'loyod ~c~r ~ha sake o.C e:;~~z~;~ily anc~ a
particular embodirnsnt described in aaaordancQ with the
requirements of 35 USC 112, but it is to be understood that the
same is not intended to be limiting and should not be so
construed inasmuch as the invention is capable of taking many
forms and variations within the scope of the appended claims.
Referring to the brawings and particularly FIGURE 1 the
forward portion of the passenger rsompartment l0 of an automobile
is shown) p,rrayed within the passenger c°mpartment Z4 are:
various ~.mterior trim panels including the instrument panel ~.4
extending across the front region thereof. The steering wheel 16
also has a trim cover 7.8 overlying i'ts central hub area.
As discussed above, there has heretofore been developed
inflatable air bag de~rices, located on each of the driver°s side
and passezzger side, acting as cushions when deployed, to safely
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absorb the momentum of the driver and passengers in the event of
a crash.
Such devices comprise inflatable "bags" st~t~xed within the
steering wheel 15 and behind the instrument panel 14 can the
passenger side. At the moment of a crash, one or mare sensors 36
detect the collision and cause activation of the air bag bY
causz.ng the flow of an inflating gas into each bag~ as by
chemical generation of the gas, which causes the bag to be
deployed within the passenger compartment to in time to absorb
the momentum of the driver and passenger.
'rhe air bag devices typ~.caJ.ly are asRemblpa into cannistern
32 3.nc:lud:f,ng ~ xeuoptable holding the faJ.ded air burg anc~t, the gn~-s
get~c~x~c~Hax~ and ignit,lan aotnpanents, l:hr-~ a~7nn.~.s~.ar:~ too~.antc~cl
lac~h;i,rtca
part~.ottF~ oI the lnt.f~riar tr;i.m. U~:a~v:laymcsnt. opc~na.ctc~fi ~rr~:
zEyc~4tixv~cl
to allow the air bags to enter the passenger compartment when
Inflated, which openings must be securely covered to prevent
tampering until the ai>: bag device is activated. Conventionally,
t,h~,s covering is provided by one ar more dears l.oaated in the
deployment opening which are opened by contact with the inflating
air bag,.
.~ccord3.rvg to the concept of the present invention, separate
daar~s rare not provided, but rather cnnr:ewtrated energy is applied
to an axes of interior trim panel members behind which the rxir
bag devices are mounted in a delineated pattern z0, 22
corresponding to the required lac~tion, shape and size of the
rec~uix~ed deployment open~.ngs.
'i~he concentrated energy is applied dust prior to inflation
J GEh~IEFIEI_ TEL. h~lo .313-64M-6530 :Jan .2~1.~a1 13:.11 F.09
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of the air bag itself, and is sufficient in magnitude to case
fracturing of the trim panel. structure along the patter~~ to
thereby farm the doors, which can be pushed open by the pressure
exerted by the bags themselves in being in~lated.
The fracture pattern may be in an "H" shape when two hinged
doors 2~, 26 are desired as far rear Facing openings. The
patterns 20, 22 provide hinging sections between the legs of the,
upward and downward facing U's comprising the H-shape of the
pattern.
In the casr~ of a °'top mounted" air bag, for ttie passenger
side, a ~;inglQ ttaar is itFtu2~ll.y amp7.oyad, anc~ in this c<~se a u~
~sh~t ~sd pat i.orn 2 >x is emp:Layed ( ~~CUt2f, 3 ) t o f o ~m Ilea Es i,ric~
1 Ey d~.~a f°
30.
The txir bag cannister :~2 is Itself activated by a c~as
generator ignition device s4 (Figure 2) itself first/ triggered bY
rune of the sensors 3r~ detecting a collision event, with a cantxol
circuit 37 processing the sensor s~.gnals a causing an electrical
activation signal to be transmitted to the air bag ignitor 34,
The detanat~.ng cord segments 3E1 are arranged in bank-t:o-back
g~~~exa.l~.y L~-shaped patterns, together forming the ti~pattern. The
~.ec,~s of the U c~nd In slightly inwardly curved sections 40 to
prevent. uncontrolled propagation of the fraa-ture line with the
unfractured trim pane. material forming a door hinge extending
between the U legs.
The detonating cord segments 38 are received into
corresponding grooves 42 let into the ityside face of the trim
panel, hexe shown as the instrument paneX ~.4.
The instrument panel l~ is conventionally constructed. of are
.lan . G
7 BEIv~IEFIE:L TEL. Ir~lr .313-614--65~U ~l ~ of :l3 ~ 12 F' ..l t.!
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outer decorative sk~.n 44 (FIGURE 4), as of flexible vinyl,
overlying a foam core 46, and a rigid backing piece 48, as of
molded plastic. ~'he grooves 42 is also formed in the backing
piece 48 and partially into the panel core 4~5.
As seen in FIGURES 5 and 5, in the embodiment of FIGURE 3, a
bridging reinforcing strip 50 extends about the grotwe pattern
42, having one side fastened to the adjacent portions of the
backing piece 48 and extending across the groove 42 to underly
the door section 26 and reinforce the same against inwa dly
pushing forces as app7.ied by incidental passenger contaot. The
bridging strip 50 includes a fold 5Z inserted into the groove 42
and extending out.ward~.x to a point closely adjacent the primer
aox d sec~rnaot 3 s . '.~h:IEV has the ~5 f e~:at of d it eat ing ttve
er~erc,~y of
the clcl,c~xlat.i.an outwardly towards thcx canneoteCl poi t.;Lc~n~s oI: th~~
care 4G and skin 44 1:a inaur.U txwatura thc~raaf.
xhe detonating cord segments 38 may ba ignited either by
extending the cord segment 38 to the ignitor 34 of the air bag
cannister 32 or may have a separate ignitor 39 as shown triggered
by a wiring connection to the air bag ignitor so that ignition
occurs at the same time the air bag is activated.
Rrimex cord is commercially available, comprised of a core
of ~rxplosive such as PLTN or ~tDX in a textile tLlb~ GOated with a
thin layer of asphalt. An outer textile saver is finished with a
wax gum composition or plastic coating.
Such primer cord will. transmit a detonating wave at a rate
between 20,000 and 24,040 feet par second, and hence the energy
generated will be applied ~.n a fraction of a millisecond, before
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inflation c~f the air big itself can occur.
This matexial is available in various charge densities, and
minimum charge sizes will generate sufficient energy to fracture
the trim panel material and form the deployment opening.
It should be appreciated that other means can be provided
for app~.ying concentrated energy in a delineated pattern, as by
an eiectrica7. dieoharge, ox a diversion of high pxessure
inflation gas through thin channels to be applied to :fracture the
trim panel in the required pattexn.
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